Case-sensitive search

[Alex Heiphetz]

I'm having problem making search case-sensitive.
For example, statement

SELECT phone FROM user WHERE user_name like '%Dan%'

returns phones from records where user_name could be  "Johnson, Dan" and 
"Vadan, Michael"

What should I do to have only "Dans" with capital "D" returned? 

Thanks in advance,
A.Heiphetz